Laptop and wireless computers and other mobile systems pose a threat to elements comprising and/or connected to a network service provider, enterprise, or other protected networks to which they reconnect after a period of connection to one or more networks and/or systems that are not part of the service provider, enterprise, or other protected network. By roaming to unknown domains, such as the Internet, and/or connecting to such domains through public, wireless, and/or otherwise less secure access nodes, such mobile systems may become infected by computer viruses, worms, backdoors, and/or countless other threats and/or exploits and/or have unauthorized software installed; have software installed on the mobile system by an operator of the protected network for the protection of the mobile system and/or the protected network removed or altered without authorization; and/or have configurations, settings, security data, and/or other data added, removed, and/or changed in unauthorized ways and/or by unauthorized person. Similarly, a stationary system may become infected, e.g., due to receipt and execution of malicious code via a network or other communication and/or a diskette and/or other removable media. Upon connecting to a protected network, a system may infect or otherwise harm resources associated with the protected network before measures can be taken to detect and prevent the spread of such infections or harm. Therefore, there is a need for a reliable way to ensure that a system does not infect or otherwise harm other network resources when connected to a protected network.